Prince Harry arrived at the High Court in London on Tuesday morning to testify in a trial against a tabloid accused of hacking phone messages. The first appearance of a member of the royal family at the bar in more than a century.

Harry accuses the publisher of the Daily Mirror of using illicit processes to gather information between 1996 and 2010. The trial is expected to last at least a few days, with the jury expected to be sequestered until the end of the trial in early June. The Daily Mirror denies the allegations against it.